Darlington Power Packs - Pioneer 780, Et al.

MarkW1973

New Member
I apologize for this duplicate post but I am new to AudioKarma and didn't even realize there was a Pioneer Forum until another user pointed it out. I found the following on the Web with respect to the SX-780 and would appreciate any input as to it's validity and whether or not this is applicable to the other SX-xxx models as well. Thank you! - Mark

"This receiver was MADE IN JAPAN (the only true collectable version) and also has the famed Darlington Power Packs. For those who don't know about the Darlingtons, when Pioneer first came out with this receiver, they used inferior output power packs. Pioneer soon learned of the problem and started using the Darlingtons early on in production." STK-0050 = Darlington Power Pack, whether it says "Darlington" on it or not.
 
At least one part is true. When I picked mine up it had one "Darlington" and one "RCA" STK0050. As for the rest, about the Darlingtons being an upgrade, I don't know. I think maybe all of the SX-780 receivers had 'em.

John
 
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"This receiver was MADE IN JAPAN (the only true collectable version) and also has the famed Darlington Power Packs. For those who don't know about the Darlingtons, when Pioneer first came out with this receiver, they used inferior output power packs. Pioneer soon learned of the problem and started using the Darlingtons early on in production." STK-0050 = Darlington Power Pack, whether it says "Darlington" on it or not.

This sounds very dubious to me, a Darlington transistor is simply two "ordinary" transistors connected so that the output of the first is then amplified by the second, therefore giving higher gain than a single transistor could. The "quality" of a transistor or power pack is determined by a lot more factors than whether or not it is a Darlington configuration. The quote above makes it sound like a Darlington power pack is a particular make rather than how the transistors are arranged.

I strongly suspect that the quote is from someone trying to "talk up" a particular model with pseudo-technological gobbledegook. Of course I could be wrong, just my $0.02.

For information on Darlington transistors see this Wikipedia article Darlington Transistor Link

- Richard B.
 
See my reply to your original thread HERE

I have been lucky to find some originals in the past when needed but there are some newer sanken seperate NPN/PNP TO-3P style darlington transistors that should be able to be fitted.
 
See my reply to your original thread HERE

I have been lucky to find some originals in the past when needed but there are some newer sanken seperate NPN/PNP TO-3P style darlington transistors that should be able to be fitted.
Thank you to everyone for the quick and informatiive replies. Where are these located so I can identify which one(s) I have in these units? (SX650, SX-950)

This is a fantastic forum. Keep up the excellent work!
 
Thank you to everyone for the quick and informatiive replies. Where are these located so I can identify which one(s) I have in these units? (SX650, SX-950)

This is a fantastic forum. Keep up the excellent work!
Physically located in the receivers? Well first, the SX-950 doesn't use darlington power packs. It uses TO-3 transistors and they can be found on the heatsink to the back right. If they are proper outputs they will be Toshiba 2SD427/2SB557. As for the SX-650, the SP-40W's are on the heatsink located at the back left of the receiver.
 
Perhaps the darlington power packs are what gives the SX-x80 series a different sound from the SX-x50 series, as these used TO3's.
I always thought the SX-x50 series was the best sounding Pioneer series.
 

For example the Pioneer SX-750 has a different sound that it's replacement the SX-780. The SX-750 had a more mellow character to it's sound (some say tube like), were the SX-780 had a more solid state sound to it.
Perhaps this was do to the use of the Darlington power packs in the SX-780, and perhaps a different amplifier design as well, as I recall they trying to eliminate other types of distortion in this design.
 
No no no, You implied that the SX-x80 series used darlington power packs and the SX-x50 used TO-3's. That simply is not true. Thats what had me going hun?
 
No no no, You implied that the SX-x80 series used darlington power packs and the SX-x50 used TO-3's. That simply is not true. Thats what had me going hun?

Perhaps I worded it a bit backwards, but I ment to say 50 series T03, 80 series powerpacks.
I have had both recievers, and am aware what's inside, and how they sound.
 
I apologize for this duplicate post but I am new to AudioKarma and didn't even realize there was a Pioneer Forum until another user pointed it out. I found the following on the Web with respect to the SX-780 and would appreciate any input as to it's validity and whether or not this is applicable to the other SX-xxx models as well. Thank you! - Mark

"This receiver was MADE IN JAPAN (the only true collectable version) and also has the famed Darlington Power Packs. For those who don't know about the Darlingtons, when Pioneer first came out with this receiver, they used inferior output power packs. Pioneer soon learned of the problem and started using the Darlingtons early on in production." STK-0050 = Darlington Power Pack, whether it says "Darlington" on it or not.

Darlington is a configuration more than a brand. A Darlington amp can be discreet transistors or an output pack like the SX-780 and its siblings. I sold Pioneer before and after the SX-x80 series came out and we didn't have many failures vs the ridiculous quantity of receivers we sold, and we would have big Pioneer Truckload sales where we'd sell over 100 SX-780s. We were also a servicing dealer, so we saw most of what was sold in the area if the customers were fed up with the other places, which they often were. If anything, the setup was incorrect and/or the heat sink compound was applied incorrectly, which led to a service bulletin, IIRC.
 
I'm with Automojo. Looking inside my 790 (black dial face version of 780) and it has TWO (2) SANYO STK-0050's screwed to the Heatsink. The 680 has the 0039's I believe.

Larry
 
AND I'm telling you that this simply is NOT true :)

Ok-the last time I had a SX-750 (bought new)was in 1987 when it got stolen, and I swear when I used to take the top of to dust it it had T03's in it-perhaps not according to you. The last time I had a SX-780, was 1990, when I sold it.
However I stand by the fact they sound quite different, as I would have kept the 750 if it wasn't stolen-didn't like the sound of the SX-780.
 
mojo,

Ok well now your mentioning specific receivers models and not referring to the entire SX-x80 and SX-x50 series. You don't seem to understand that not ALL x80 series used darlington power packs and ALL x50 series used TO-3's as you have implied. Understand? :smoke:
 
I just ran over to my neighbors, who has a 650. It HAS Darlingtons although they are not STK's. Apparently Most people use Darlington and STK interchangeably.

They DO sound different. My 790 sounds kinda flat, and thin across the board, compared to the neighbors 650. And we both have them hooked up to Bose 301's so we can pretty much set between the speakers in either house and tell the differences. The noise floor is better on the 790. As is the total wattage. Other than that, it's pretty much a wash.

Larry
 
mojo,

Ok well now your mentioning specific receivers models and not referring to the entire SX-x80 and SX-x50 series. You don't seem to understand that not ALL x80 series used darlington power packs and ALL x50 series used TO-3's as you have implied. Understand? :smoke:

Look Overload, I understand. I was talking about the SX-750 and SX-780 concerning the power transistors.
Regarding the sound- I was talking generally about the SX- 50 series vs.the SX-80 series, they have a different sound to them, as I have heard quite a few of each model-only owned the 750 and 780. In addition, they were trying to lower THD specs and intermodulation distortion specs and the SX 80' series, over the previous 50 series, and perhaps in part, this accounts for the difference in sound.

Perhaps if you replyed to my post with more than "hun" (or was it "huh":scratch2:), or one or two words, it might be more helpful, and possibly less rude to boot.
 
Perhaps the darlington power packs are what gives the SX-x80 series a different sound from the SX-x50 series, as these used TO3's.
well I wasn't being rude, some people are as thick as shit though, now THAT might be construed as rude, so interpret a way. Just re-read what ya said. I'm out of this one. To the OP, sorry for the off topic and good luck!
 
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